In a large heat-safe microwaveable bowl, add butter and heat in the microwave until melted. Remove and whisk in sugar until well combined. Set bowl aside and let cool to lukewarm.

Meanwhile, in a medium bowl, whisk together flours, baking powder and salt.

Whisk in eggs, one at a time, beating until well combined after each. Mix in vanilla and rum flavoring. Add dry ingredients and stir just until combined - fold in walnuts. Scoop mixture into a 9" x 13" baking pan coated with nonstick cooking spray - spread batter using an offset spatula to evenly cover the bottom.

Place pan into the oven and bake until the top is shiny and the edges just begin to pull away from the side of the pan, about 18 to 24 minutes. Do not overbake - a toothpick placed in the center should come out with moist crumbs attached. Remove from the oven and let cool completely before cutting into bars.

I love the addition of the whole wheat flour. These would be good with maybe a touch less flour and butterscotch chips on the inside. They sounds lovely...without the nuts as I too am not a fan in baked goods.

Joe, Thanks. The funny thing is, I was spring cleaning this weekend and found a bottle of rum extract. I'm planning on making these tonight, adding butterscotch chips and walnuts. I actually am counting on the fact that I don't really like butterscotch chips, LOL, to prevent myself from over-eating these. My teenagers with their fast metabolisms can scarf them down.

Joe, I did make these last night, in a 9" x 9" pan. They took a pretty long time to bake, around 40-45 minutes. But they came out really good! I definitely liked the walnuts in them. I think they did help cut the sweetness. I cut them into really small pieces and they were perfect. Jennifer

We have made these cookies a lot and LOVE them. But we are having trouble getting the consistency correct. If we bake them less than 24 minutes, the inside looks gooey (tastes great, but I don't think that's what they are supposed to look like). But, to get the inside to look "done", we have to bake them almost 40 minutes and then they are too done. Any suggestions?